IBM transistor replacements
elson at pico-systems.com
Fri Nov 26 19:11:24 CST 2021
On 11/26/21 3:52 PM, Al via cctalk wrote:
> Dear all,
> A while ago I received an IBM 3286 printer, annoyingly
> some of the transistors in the printer section have been
> corroded. What I am having trouble with is reading the
> part codes and finding a modern equivalent of them.
> There are two types.
> One has a Ti logo and two sets of numbers (attached). Does
> anybody know which numbers are the part numbers and if
> they are IBM house numbered?
> Photos of the Ti transistors and card assembly:
> The other is an IBM transistor with what appears to be a 3
> digit part code; for which I have been pointed to a list
> of house numbering and equivalents on the 1401 website. I
> was told the list is much older and I fear it might be out
> of date. However there is an entry for the part codes on
> my IBM transistors.
> Should I trust the list for replacements?
The cards appear to be SLT-style fabrication, it seems there
may even be SLT modules on one of them (the 1/2" square
The 1401 list would be for SMS cards, they were yellow
paper-phenolic cards with TO-5 and TO-18 discrete Germanium
transistors. The SLT vintage were generally all Silicon
Almost all this stuff had IBM house numbers.
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